There is a proposed refrigeration cycle apparatus in which an expansion mechanism is provided instead of a decompressor, pressure energy generated at the time of expansion is recovered as power, thereby enhancing COP (see patent documents 1 and 2 for example). The expansion mechanism used in such a refrigeration cycle apparatus is rotated by a pressure difference between a high pressure (pressures in an outlet of the compression mechanism, a radiator and an inlet of the expansion mechanism) and a low pressure (pressures in an outlet of the expansion mechanism, the evaporator, and an inlet of the compression mechanism). Usually, when the refrigeration cycle apparatus is stopped, the high pressure and the low pressure are equalized, and a pressure difference is not generated between the high pressure and the low pressure until the compression mechanism is started.
[Patent Document 1] Japanese Patent Application Laid-open No. S51-65456
[Patent Document 2] Japanese Patent Application Laid-open No. S56-112896
In the conventional techniques, however, since the expansion mechanism is rotated by the pressure difference between the high pressure and the low pressure and the power is recovered, there is a problem that it is difficult to generate the pressure difference at the time of starting operation of the expansion mechanism, the operation or behavior of the expansion mechanism becomes unstable, and it takes a long time to start the refrigeration cycle apparatus.
To solve the above problem, in a refrigeration cycle apparatus having an expansion mechanism, it is an object of the present invention to swiftly generate a pressure difference upstream and downstream of the expansion mechanism, thereby enhancing the starting performance of the refrigeration cycle apparatus.
According to a control method of the refrigeration cycle apparatus of the present invention, in the refrigeration cycle apparatus having the expansion mechanism, it is possible to swiftly generate a pressure difference upstream and downstream of the expansion mechanism, thereby enhancing the starting performance of the refrigeration cycle apparatus.